Question

i have a trouble and i need your help. Here’s my code:

public class CircleElement : ContentControl
{

public ContentControl me;
private FrameworkElement _parent;

public CircleElement()
{
  if (_parent != null)
  {
    me = (ContentControl)_parent.FindResource("CircleRes");
    me.Style = (Style)_parent.FindResource("CircleStyle");
  }

}

The CircleElement inherits the ContentControl and I would like to assign the resource “CircleRes” and the style “CircleStyle” to it. Something like:

this = (ContentControl)_parent.FindResource("CircleRes");
this.Style = (Style)_parent.FindResource("CircleStyle");

This thing is not allowable.So to get around this problem I instantiated the ContentControl me element; but the code is a little messy!! How to get it more “elegant” ???

Thanks in advance

Paolo

Answer 1

Your requirement is a little strange but it is achievable in multiple ways…

Instead of having another content control (i.e. me) why not set this control’s Content itself?

    this.Content
           = (ContentControl)_parent.FindResource("CircleRes"); 
    ((ContentControl)(this.Content)).Style
           = (Style)_parent.FindResource("CircleStyle"); //*** Potential problem

Problem: The Potential problem statement is marked this way because your code (and mine too) sets the style "CircleStyle" to "CircleRes" resource by reference.

How? me or ((ContentControl)(this.Content)) is nothing but "CircleRes" resource!

This means if "CircleRes" is referred in some other place, it will carry the "CircleStyle" as its own style along with it. And if you set some new Style to "CircleRes" somewhere else then it will overwrite the Style of "CircleRes" wherever is used, including the above code (where intended style is "CircleStyle")

Solution: Use ContentTemplate instead. Templates don’t cause a visual’s by instance reference.

So actually you should have a DataTemplate (say “CircleResTemplate”) and set that as ContentTemplate to CircleElement class.

   this.ContentTemplate
       = (DataTemplate)_parent.FindResource("CircleResTemplate");
   this.Style
       = (Style)_parent.FindResource("CircleStyle"); 

Let me know if this answers your question.